xen/io/xnbo.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Xen network backend - mac client edition.
 *
 * A driver that sits above an existing GLDv3/Nemo MAC driver and
 * relays packets to/from that driver from/to a guest domain.
 */

#ifdef DEBUG
#define XNBO_DEBUG 1
#endif /* DEBUG */

#include "xnb.h"

#include <sys/sunddi.h>
#include <sys/ddi.h>
#include <sys/modctl.h>
#include <sys/strsubr.h>
#include <sys/mac_client.h>
#include <sys/mac_provider.h>
#include <sys/mac_client_priv.h>
#include <sys/mac.h>
#include <net/if.h>
#include <sys/dlpi.h>
#include <sys/pattr.h>
#include <xen/sys/xenbus_impl.h>
#include <xen/sys/xendev.h>
#include <sys/sdt.h>
#include <sys/note.h>

#ifdef XNBO_DEBUG
boolean_t xnbo_cksum_offload_to_peer = B_TRUE;
boolean_t xnbo_cksum_offload_from_peer = B_TRUE;
#endif /* XNBO_DEBUG */

/* Track multicast addresses. */
typedef struct xmca {
    struct xmca *next;
    ether_addr_t addr;
} xmca_t;

/* State about this device instance. */
typedef struct xnbo {
    mac_handle_t        o_mh;
    mac_client_handle_t o_mch;
    mac_unicast_handle_t    o_mah;
    mac_promisc_handle_t    o_mphp;
    boolean_t       o_running;
    boolean_t       o_promiscuous;
    uint32_t        o_hcksum_capab;
    xmca_t          *o_mca;
    char            o_link_name[LIFNAMSIZ];
    boolean_t       o_need_rx_filter;
    boolean_t       o_need_setphysaddr;
    boolean_t       o_multicast_control;
} xnbo_t;

static void xnbo_close_mac(xnb_t *);
static void i_xnbo_close_mac(xnb_t *, boolean_t);

/*
 * Packets from the peer come here.  We pass them to the mac device.
 */
static void
xnbo_to_mac(xnb_t *xnbp, mblk_t *mp)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;

    ASSERT(mp != NULL);

    if (!xnbop->o_running) {
        xnbp->xnb_stat_tx_too_early++;
        goto fail;
    }

    if (mac_tx(xnbop->o_mch, mp, 0,
        MAC_DROP_ON_NO_DESC, NULL) != NULL) {
        xnbp->xnb_stat_mac_full++;
    }

    return;

fail:
    freemsgchain(mp);
}

/*
 * Process the checksum flags `flags' provided by the peer for the
 * packet `mp'.
 */
static mblk_t *
xnbo_cksum_from_peer(xnb_t *xnbp, mblk_t *mp, uint16_t flags)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;

    ASSERT(mp->b_next == NULL);

    if ((flags & NETTXF_csum_blank) != 0) {
        uint32_t capab = xnbop->o_hcksum_capab;

#ifdef XNBO_DEBUG
        if (!xnbo_cksum_offload_from_peer)
            capab = 0;
#endif /* XNBO_DEBUG */

        /*
         * The checksum in the packet is blank.  Determine
         * whether we can do hardware offload and, if so,
         * update the flags on the mblk according.  If not,
         * calculate and insert the checksum using software.
         */
        mp = xnb_process_cksum_flags(xnbp, mp, capab);
    }

    return (mp);
}

/*
 * Calculate the checksum flags to be relayed to the peer for the
 * packet `mp'.
 */
static uint16_t
xnbo_cksum_to_peer(xnb_t *xnbp, mblk_t *mp)
{
    _NOTE(ARGUNUSED(xnbp));
    uint16_t r = 0;
    uint32_t pflags, csum;

#ifdef XNBO_DEBUG
    if (!xnbo_cksum_offload_to_peer)
        return (0);
#endif /* XNBO_DEBUG */

    /*
     * We might also check for HCK_PARTIALCKSUM here and,
     * providing that the partial checksum covers the TCP/UDP
     * payload, return NETRXF_data_validated.
     *
     * It seems that it's probably not worthwhile, as even MAC
     * devices which advertise HCKSUM_INET_PARTIAL in their
     * capabilities tend to use HCK_FULLCKSUM on the receive side
     * - they are actually saying that in the output path the
     * caller must use HCK_PARTIALCKSUM.
     *
     * Then again, if a NIC supports HCK_PARTIALCKSUM in its'
     * output path, the host IP stack will use it. If such packets
     * are destined for the peer (i.e. looped around) we would
     * gain some advantage.
     */

    mac_hcksum_get(mp, NULL, NULL, NULL, &csum, &pflags);

    /*
     * If the MAC driver has asserted that the checksum is
     * good, let the peer know.
     */
    if (((pflags & HCK_FULLCKSUM) != 0) &&
        (((pflags & HCK_FULLCKSUM_OK) != 0) ||
        (csum == 0xffff)))
        r |= NETRXF_data_validated;

    return (r);
}

/*
 * Packets from the mac device come here.  We pass them to the peer.
 */
/*ARGSUSED*/
static void
xnbo_from_mac(void *arg, mac_resource_handle_t mrh, mblk_t *mp,
    boolean_t loopback)
{
    xnb_t *xnbp = arg;

    mp = xnb_copy_to_peer(xnbp, mp);

    if (mp != NULL)
        freemsgchain(mp);
}

/*
 * Packets from the mac device come here. We pass them to the peer if
 * the destination mac address matches or it's a multicast/broadcast
 * address.
 */
static void
xnbo_from_mac_filter(void *arg, mac_resource_handle_t mrh, mblk_t *mp,
    boolean_t loopback)
{
    _NOTE(ARGUNUSED(loopback));
    xnb_t *xnbp = arg;
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    mblk_t *next, *keep, *keep_head, *free, *free_head;

    keep = keep_head = free = free_head = NULL;

#define ADD(list, bp)               \
    if (list != NULL)           \
        list->b_next = bp;      \
    else                    \
        list##_head = bp;       \
    list = bp;

    for (; mp != NULL; mp = next) {
        mac_header_info_t hdr_info;

        next = mp->b_next;
        mp->b_next = NULL;

        if (mac_header_info(xnbop->o_mh, mp, &hdr_info) != 0) {
            ADD(free, mp);
            continue;
        }

        if ((hdr_info.mhi_dsttype == MAC_ADDRTYPE_BROADCAST) ||
            (hdr_info.mhi_dsttype == MAC_ADDRTYPE_MULTICAST)) {
            ADD(keep, mp);
            continue;
        }

        if (bcmp(hdr_info.mhi_daddr, xnbp->xnb_mac_addr,
            sizeof (xnbp->xnb_mac_addr)) == 0) {
            ADD(keep, mp);
            continue;
        }

        ADD(free, mp);
    }
#undef  ADD

    if (keep_head != NULL)
        xnbo_from_mac(xnbp, mrh, keep_head, B_FALSE);

    if (free_head != NULL)
        freemsgchain(free_head);
}

static boolean_t
xnbo_open_mac(xnb_t *xnbp, char *mac)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    int err;
    const mac_info_t *mi;
    void (*rx_fn)(void *, mac_resource_handle_t, mblk_t *, boolean_t);
    struct ether_addr ea;
    uint_t max_sdu;
    mac_diag_t diag;

    if ((err = mac_open_by_linkname(mac, &xnbop->o_mh)) != 0) {
        cmn_err(CE_WARN, "xnbo_open_mac: "
            "cannot open mac for link %s (%d)", mac, err);
        return (B_FALSE);
    }
    ASSERT(xnbop->o_mh != NULL);

    mi = mac_info(xnbop->o_mh);
    ASSERT(mi != NULL);

    if (mi->mi_media != DL_ETHER) {
        cmn_err(CE_WARN, "xnbo_open_mac: "
            "device is not DL_ETHER (%d)", mi->mi_media);
        i_xnbo_close_mac(xnbp, B_TRUE);
        return (B_FALSE);
    }
    if (mi->mi_media != mi->mi_nativemedia) {
        cmn_err(CE_WARN, "xnbo_open_mac: "
            "device media and native media mismatch (%d != %d)",
            mi->mi_media, mi->mi_nativemedia);
        i_xnbo_close_mac(xnbp, B_TRUE);
        return (B_FALSE);
    }

    mac_sdu_get(xnbop->o_mh, NULL, &max_sdu);
    if (max_sdu > XNBMAXPKT) {
        cmn_err(CE_WARN, "xnbo_open_mac: mac device SDU too big (%d)",
            max_sdu);
        i_xnbo_close_mac(xnbp, B_TRUE);
        return (B_FALSE);
    }

    /*
     * MAC_OPEN_FLAGS_MULTI_PRIMARY is relevant when we are migrating a
     * guest on the localhost itself. In this case we would have the MAC
     * client open for the guest being migrated *and* also for the
     * migrated guest (i.e. the former will be active till the migration
     * is complete when the latter will be activated). This flag states
     * that it is OK for mac_unicast_add to add the primary MAC unicast
     * address multiple times.
     */
    if (mac_client_open(xnbop->o_mh, &xnbop->o_mch, NULL,
        MAC_OPEN_FLAGS_USE_DATALINK_NAME |
        MAC_OPEN_FLAGS_MULTI_PRIMARY) != 0) {
        cmn_err(CE_WARN, "xnbo_open_mac: "
            "error (%d) opening mac client", err);
        i_xnbo_close_mac(xnbp, B_TRUE);
        return (B_FALSE);
    }

    if (xnbop->o_need_rx_filter)
        rx_fn = xnbo_from_mac_filter;
    else
        rx_fn = xnbo_from_mac;

    err = mac_unicast_add_set_rx(xnbop->o_mch, NULL, MAC_UNICAST_PRIMARY,
        &xnbop->o_mah, 0, &diag, xnbop->o_multicast_control ? rx_fn : NULL,
        xnbp);
    if (err != 0) {
        cmn_err(CE_WARN, "xnbo_open_mac: failed to get the primary "
            "MAC address of %s: %d", mac, err);
        i_xnbo_close_mac(xnbp, B_TRUE);
        return (B_FALSE);
    }
    if (!xnbop->o_multicast_control) {
        err = mac_promisc_add(xnbop->o_mch, MAC_CLIENT_PROMISC_ALL,
            rx_fn, xnbp, &xnbop->o_mphp, MAC_PROMISC_FLAGS_NO_TX_LOOP |
            MAC_PROMISC_FLAGS_VLAN_TAG_STRIP);
        if (err != 0) {
            cmn_err(CE_WARN, "xnbo_open_mac: "
                "cannot enable promiscuous mode of %s: %d",
                mac, err);
            i_xnbo_close_mac(xnbp, B_TRUE);
            return (B_FALSE);
        }
        xnbop->o_promiscuous = B_TRUE;
    }

    if (xnbop->o_need_setphysaddr) {
        err = mac_unicast_primary_set(xnbop->o_mh, xnbp->xnb_mac_addr);
        /* Warn, but continue on. */
        if (err != 0) {
            bcopy(xnbp->xnb_mac_addr, ea.ether_addr_octet,
                ETHERADDRL);
            cmn_err(CE_WARN, "xnbo_open_mac: "
                "cannot set MAC address of %s to "
                "%s: %d", mac, ether_sprintf(&ea), err);
        }
    }

    if (!mac_capab_get(xnbop->o_mh, MAC_CAPAB_HCKSUM,
        &xnbop->o_hcksum_capab))
        xnbop->o_hcksum_capab = 0;

    xnbop->o_running = B_TRUE;

    return (B_TRUE);
}

static void
xnbo_close_mac(xnb_t *xnbp)
{
    i_xnbo_close_mac(xnbp, B_FALSE);
}

static void
i_xnbo_close_mac(xnb_t *xnbp, boolean_t locked)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    xmca_t *loop;

    ASSERT(!locked || MUTEX_HELD(&xnbp->xnb_state_lock));

    if (xnbop->o_mh == NULL)
        return;

    if (xnbop->o_running)
        xnbop->o_running = B_FALSE;

    if (!locked)
        mutex_enter(&xnbp->xnb_state_lock);
    loop = xnbop->o_mca;
    xnbop->o_mca = NULL;
    if (!locked)
        mutex_exit(&xnbp->xnb_state_lock);

    while (loop != NULL) {
        xmca_t *next = loop->next;

        DTRACE_PROBE3(mcast_remove,
            (char *), "close",
            (void *), xnbp,
            (etheraddr_t *), loop->addr);
        (void) mac_multicast_remove(xnbop->o_mch, loop->addr);
        kmem_free(loop, sizeof (*loop));
        loop = next;
    }

    if (xnbop->o_promiscuous) {
        if (xnbop->o_mphp != NULL) {
            mac_promisc_remove(xnbop->o_mphp);
            xnbop->o_mphp = NULL;
        }
        xnbop->o_promiscuous = B_FALSE;
    } else {
        if (xnbop->o_mch != NULL)
            mac_rx_clear(xnbop->o_mch);
    }

    if (xnbop->o_mah != NULL) {
        (void) mac_unicast_remove(xnbop->o_mch, xnbop->o_mah);
        xnbop->o_mah = NULL;
    }

    if (xnbop->o_mch != NULL) {
        mac_client_close(xnbop->o_mch, 0);
        xnbop->o_mch = NULL;
    }

    mac_close(xnbop->o_mh);
    xnbop->o_mh = NULL;
}

/*
 * Hotplug has completed and we are connected to the peer. We have all
 * the information we need to exchange traffic, so open the MAC device
 * and configure it appropriately.
 */
static boolean_t
xnbo_start_connect(xnb_t *xnbp)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;

    return (xnbo_open_mac(xnbp, xnbop->o_link_name));
}

/*
 * The guest has successfully synchronize with this instance. We read
 * the configuration of the guest from xenstore to check whether the
 * guest requests multicast control. If not (the default) we make a
 * note that the MAC device needs to be used in promiscious mode.
 */
static boolean_t
xnbo_peer_connected(xnb_t *xnbp)
{
    char *oename;
    int request;
    xnbo_t *xnbop = xnbp->xnb_flavour_data;

    oename = xvdi_get_oename(xnbp->xnb_devinfo);

    if (xenbus_scanf(XBT_NULL, oename,
        "request-multicast-control", "%d", &request) != 0)
        request = 0;
    xnbop->o_multicast_control = (request > 0);

    return (B_TRUE);
}

/*
 * The guest domain has closed down the inter-domain connection. We
 * close the underlying MAC device.
 */
static void
xnbo_peer_disconnected(xnb_t *xnbp)
{
    xnbo_close_mac(xnbp);
}

/*
 * The hotplug script has completed. We read information from xenstore
 * about our configuration, most notably the name of the MAC device we
 * should use.
 */
static boolean_t
xnbo_hotplug_connected(xnb_t *xnbp)
{
    char *xsname;
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    int need;

    xsname = xvdi_get_xsname(xnbp->xnb_devinfo);

    if (xenbus_scanf(XBT_NULL, xsname,
        "nic", "%s", xnbop->o_link_name) != 0) {
        cmn_err(CE_WARN, "xnbo_connect: "
            "cannot read nic name from %s", xsname);
        return (B_FALSE);
    }

    if (xenbus_scanf(XBT_NULL, xsname,
        "SUNW-need-rx-filter", "%d", &need) != 0)
        need = 0;
    xnbop->o_need_rx_filter = (need > 0);

    if (xenbus_scanf(XBT_NULL, xsname,
        "SUNW-need-set-physaddr", "%d", &need) != 0)
        need = 0;
    xnbop->o_need_setphysaddr = (need > 0);

    return (B_TRUE);
}

/*
 * Find the multicast address `addr', return B_TRUE if it is one that
 * we receive. If `remove', remove it from the set received.
 */
static boolean_t
xnbo_mcast_find(xnb_t *xnbp, ether_addr_t *addr, boolean_t remove)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    xmca_t *prev, *del, *this;

    ASSERT(MUTEX_HELD(&xnbp->xnb_state_lock));
    ASSERT(xnbop->o_promiscuous == B_FALSE);

    prev = del = NULL;

    this = xnbop->o_mca;

    while (this != NULL) {
        if (bcmp(&this->addr, addr, sizeof (this->addr)) == 0) {
            del = this;
            if (remove) {
                if (prev == NULL)
                    xnbop->o_mca = this->next;
                else
                    prev->next = this->next;
            }
            break;
        }

        prev = this;
        this = this->next;
    }

    if (del == NULL)
        return (B_FALSE);

    if (remove) {
        DTRACE_PROBE3(mcast_remove,
            (char *), "remove",
            (void *), xnbp,
            (etheraddr_t *), del->addr);
        mac_multicast_remove(xnbop->o_mch, del->addr);
        kmem_free(del, sizeof (*del));
    }

    return (B_TRUE);
}

/*
 * Add the multicast address `addr' to the set received.
 */
static boolean_t
xnbo_mcast_add(xnb_t *xnbp, ether_addr_t *addr)
{
    xnbo_t *xnbop = xnbp->xnb_flavour_data;
    boolean_t r = B_FALSE;

    ASSERT(xnbop->o_promiscuous == B_FALSE);

    mutex_enter(&xnbp->xnb_state_lock);

    if (xnbo_mcast_find(xnbp, addr, B_FALSE)) {
        r = B_TRUE;
    } else if (mac_multicast_add(xnbop->o_mch,
        (const uint8_t *)addr) == 0) {
        xmca_t *mca;

        DTRACE_PROBE3(mcast_add,
            (char *), "add",
            (void *), xnbp,
            (etheraddr_t *), addr);

        mca = kmem_alloc(sizeof (*mca), KM_SLEEP);
        bcopy(addr, &mca->addr, sizeof (mca->addr));

        mca->next = xnbop->o_mca;
        xnbop->o_mca = mca;

        r = B_TRUE;
    }

    mutex_exit(&xnbp->xnb_state_lock);

    return (r);
}

/*
 * Remove the multicast address `addr' from the set received.
 */
static boolean_t
xnbo_mcast_del(xnb_t *xnbp, ether_addr_t *addr)
{
    boolean_t r;

    mutex_enter(&xnbp->xnb_state_lock);
    r = xnbo_mcast_find(xnbp, addr, B_TRUE);
    mutex_exit(&xnbp->xnb_state_lock);

    return (r);
}

static int
xnbo_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
    static xnb_flavour_t flavour = {
        xnbo_to_mac, xnbo_peer_connected, xnbo_peer_disconnected,
        xnbo_hotplug_connected, xnbo_start_connect,
        xnbo_cksum_from_peer, xnbo_cksum_to_peer,
        xnbo_mcast_add, xnbo_mcast_del,
    };
    xnbo_t *xnbop;

    switch (cmd) {
    case DDI_ATTACH:
        break;
    case DDI_RESUME:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    xnbop = kmem_zalloc(sizeof (*xnbop), KM_SLEEP);

    if (xnb_attach(dip, &flavour, xnbop) != DDI_SUCCESS) {
        kmem_free(xnbop, sizeof (*xnbop));
        return (DDI_FAILURE);
    }

    return (DDI_SUCCESS);
}

static int
xnbo_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
    xnb_t *xnbp = ddi_get_driver_private(dip);
    xnbo_t *xnbop = xnbp->xnb_flavour_data;

    switch (cmd) {
    case DDI_DETACH:
        break;
    case DDI_SUSPEND:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    mutex_enter(&xnbp->xnb_tx_lock);
    mutex_enter(&xnbp->xnb_rx_lock);

    if (!xnbp->xnb_detachable || xnbp->xnb_connected ||
        (xnbp->xnb_tx_buf_count > 0)) {
        mutex_exit(&xnbp->xnb_rx_lock);
        mutex_exit(&xnbp->xnb_tx_lock);

        return (DDI_FAILURE);
    }

    mutex_exit(&xnbp->xnb_rx_lock);
    mutex_exit(&xnbp->xnb_tx_lock);

    xnbo_close_mac(xnbp);
    kmem_free(xnbop, sizeof (*xnbop));

    xnb_detach(dip);

    return (DDI_SUCCESS);
}

static struct cb_ops cb_ops = {
    nulldev,        /* open */
    nulldev,        /* close */
    nodev,          /* strategy */
    nodev,          /* print */
    nodev,          /* dump */
    nodev,          /* read */
    nodev,          /* write */
    nodev,          /* ioctl */
    nodev,          /* devmap */
    nodev,          /* mmap */
    nodev,          /* segmap */
    nochpoll,       /* poll */
    ddi_prop_op,        /* cb_prop_op */
    0,          /* streamtab  */
    D_NEW | D_MP | D_64BIT  /* Driver compatibility flag */
};

static struct dev_ops ops = {
    DEVO_REV,       /* devo_rev */
    0,          /* devo_refcnt  */
    nulldev,        /* devo_getinfo */
    nulldev,        /* devo_identify */
    nulldev,        /* devo_probe */
    xnbo_attach,        /* devo_attach */
    xnbo_detach,        /* devo_detach */
    nodev,          /* devo_reset */
    &cb_ops,        /* devo_cb_ops */
    (struct bus_ops *)0,    /* devo_bus_ops */
    NULL,           /* devo_power */
    ddi_quiesce_not_needed,     /* devo_quiesce */
};

static struct modldrv modldrv = {
    &mod_driverops, "xnbo driver", &ops,
};

static struct modlinkage modlinkage = {
    MODREV_1, &modldrv, NULL
};

int
_init(void)
{
    return (mod_install(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

int
_fini(void)
{
    return (mod_remove(&modlinkage));
}